/*
 * Copyright 2016 resin.io
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * A button with a progress bar inside.
 *
 * From http://tympanus.net/Development/ProgressButtonStyles/
 *
 * The state of the progress bar is controller by the width, in percentage,
 * of `.progress-button__bar`.
 *
 * If there is an action in place, the `active` attribute must be set to `true`.
 * This is useful to determine if the progress bar is paused from the point of view
 * of the styling.
 *
 * You can optionally pass the `.progress-button--striped` modified to get a striped
 * progress bar.
 *
 * The stripe implementation idea was taken from:
 *
 *   https://css-tricks.com/css3-progress-bars/
 *
 * Usage:
 *
 * <button class="progress-button" active="true">
 *   <span class="progress-button__content">Button text</span>
 *   <span class="progress-button__bar" style="width: 50%;"></span>
 * </button>
 */

$progress-button-stripes-width: 20px;
$progress-button-stripes-animation-duration: 1s;

.progress-button {
  @extend .button;
  @extend .button-primary;
  
  overflow: hidden;

  &[active="true"] {
    background-color: $palette-theme-warning-background;
  }

  .progress-button__bar {
    background-color: lighten($palette-theme-warning-background, 5%);
  }

  &.progress-button--striped {
    $progress-button-stripes-background-color: desaturate($palette-theme-warning-background, 5%);
    $progress-button-stripes-foreground-color: desaturate(darken($palette-theme-warning-background, 18%), 20%);

    // Notice that we add `0.01` to certain gradient stop positions.
    // That workarounds a Chrome rendering issue where diagonal
    // lines look spiky.
    // See https://github.com/resin-io/etcher/issues/472
    background-image: -webkit-gradient(linear, 0 0, 100% 100%,
      color-stop(0.25, $progress-button-stripes-foreground-color),
      color-stop(0.25 + 0.01, $progress-button-stripes-background-color),
      color-stop(0.50, $progress-button-stripes-background-color),
      color-stop(0.50 + 0.01, $progress-button-stripes-foreground-color),
      color-stop(0.75, $progress-button-stripes-foreground-color),
      color-stop(0.75 + 0.01, $progress-button-stripes-background-color),
      to($progress-button-stripes-background-color));

    .progress-button__bar {
      background-color: lighten($palette-theme-warning-background, 5%);
    }

  }

}

// Prevent the button from being clickable
// when it has an active progress bar.
.progress-button[active="true"] {
  @extend .button-no-hover;
}

.progress-button__content {
  position: relative;
  z-index: 10;
}

.progress-button__bar {
  position: absolute;
  left: 0;
  top: 0;

  width: 0;
  height: 100%;

  // Subtle progress bar animation
  transition: width 0.3s;

}

.progress-button--striped {
  background-size: $progress-button-stripes-width $progress-button-stripes-width;
  animation: progress-button-stripes $progress-button-stripes-animation-duration linear infinite;
  overflow: hidden;
}

@keyframes progress-button-stripes {

  0% {
    background-position: 0 0;
  }

  100% {
    background-position: $progress-button-stripes-width $progress-button-stripes-width;
  }

}
